Feline comorbidities: What do we really know about feline triaditis?

Abstract

Practical relevance: Feline triaditis describes concurrent pancreatitis, cholangitis and inflammatory bowel disease (IBD). The reported prevalence is 17-39% in ill referral patients. While the aetiology is poorly understood, it is known to include infectious, autoimmune and physical components. What is not known is whether different organs are affected by different diseases, or the same process; indeed, triaditis may be part of a multiorgan inflammatory disease. Feline gastrointestinal tract anatomy plays its role too. Specifically, the short small intestine, high bacterial load and anatomic feature whereby the pancreatic duct joins the common bile duct before entering the duodenal papilla all increase the risk of bacterial reflux and parenchymal inflammation. Inflammation may also be a sequela of bowel bacterial translocation and systemic bacteraemia.

Diagnostic challenges: Cholangitis, pancreatitis and IBD manifest with overlapping, vague and non-specific clinical signs. Cholangitis may be accompanied by increased serum liver enzymes, total bilirubin and bile acid concentrations, and variable ultrasonographic changes. A presumptive diagnosis of pancreatitis is based on increased serum pancreatic lipase immunoreactivity or feline pancreas-specific lipase, and/or abnormal pancreatic changes on ultrasonography, though these tests have low sensitivity. Diagnosis of IBD is challenging without histopathology; ultrasound findings vary from normal to mucosal thickening or loss of layering. Triaditis may cause decreased serum folate or cobalamin (B12) concentrations due to intestinal disease and/or pancreatitis. Triaditis can only be confirmed with histopathology; hence, it remains a presumptive diagnosis in most cases.

Evidence base: The literature on feline triaditis, pancreatitis, cholangitis and IBD is reviewed, focusing on histopathology, clinical significance and diagnostic challenges. Current management recommendations are provided. Further studies are needed to understand the complex pathophysiology, and in turn improve diagnosis and treatment.

Keywords: IBD; Triaditis; cholangitis; inflammatory bowel disease; pancreatitis.

Figure 1

Illustration showing the close proximity and anatomical relationship between the liver, pancreas and duodenum of the cat. The pancreatic duct joins the bile duct before entering the duodenum at the papilla, which may predispose to ascending infections of both the liver and pancreas, and potentially multiorgan inflammation. Of note, the accessory pancreatic duct is present in only around 20% of cats. Courtesy of Ceva

Figure 2

Siamese cat with triaditis that developed vasculitis. Courtesy of Kerry Rolph

Figure 3

Burmese cat diagnosed with cholangitis. Jaundice is usually seen after a five- to-10-fold increase in serum bilirubin concentration

Figure 4

Same cat as in Figure 3, receiving a lactulose enema for treatment of hepatic encephalopathy that developed secondarily to neutrophilic cholangitis. Lactulose therapy is considered a first-line treatment and can be administered orally and/or rectally. Note, however, that there are high risks associated with oral administration in cats with decreased mentation (eg, aspiration pneumonia), so rectal administration is preferred in these cases

Figure 5

Biliary bypass surgery in a 7-year-old cat with a biliary obstruction and acute pancreatitis. This image shows the right limb of the pancreas (black arrow) and the biliary bypass in situ (the gallbladder has been sutured to the duodenum [white arrow]). Pancreatic biopsies were also acquired. Courtesy of Donald Yool

Figure 6

Assisted feeding through an oesophagostomy tube may be highly beneficial in the management of feline triaditis. Cats should always be offered food before tube feeding. This cat is eating warm chicken while also being fed through its oesophagostomy tube. There is an empty syringe beside the cat as the tube was also used to administer medications